WASHINGTON (AP) - Small businesses in Washington will be required to buy employee health insurance through a city-run exchange beginning in 2014.

The District of Columbia is combining its health care exchange markets for individuals and small businesses that have fewer than 50 employees. The D.C. Health Benefit Exchange Authority voted unanimously Wednesday to combine the health exchanges, despite opposition from businesses. Some said the exchange will lead to higher costs.

D.C. officials say the decision was based on the city's small individual-insurance market. The city has few uninsured people. So D.C. Councilmember David Catania says the merger will create a sufficient pool for the health care exchange to bring down costs.

One state, Vermont, is taking a similar approach. Other states have more uninsured people and larger populations.